A microwave oven has a power requirement of 1248 W. A frozen dinner requires 6.9 min to heat on full power.

Question

(a) How much electrical energy (in kWh) is used?

(b) If the cost of electricity is 12 cents per kWh, how much does it cost to heat the dinner?

Answer 1

look at the units

electrical energy (in kWh) = power (in kW) x time (in hour)

cost of electricity = [electrical energy (in kWh)]*(12 cents/ kWh)

Answer 2

1.72